Surface lattice dynamics and electron–phonon interaction in cesium ultra-thin films

2017 ◽  
Vol 19 (25) ◽  
pp. 16358-16364 ◽  
Author(s):  
D. Campi ◽  
M. Bernasconi ◽  
G. Benedek ◽  
A. P. Graham ◽  
J. P. Toennies
Keyword(s):  
Ultrathin Films ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Phonon Interaction ◽  
Phonon Dispersion Curves ◽  
Helium Atom Scattering ◽  
Electron Phonon Interaction ◽  
Atom Scattering ◽  
Density Functional Perturbation Theory ◽  
Mass Enhancement

The phonon dispersion curves of ultrathin films of Cs(110) on Pt(111) measured with inelastic helium atom scattering (HAS) are reported and compared with density-functional perturbation theory calculations. The mass-enhancement factor is derived from the temperature dependence of the HAS Debye–Waller exponent.

scholarly journals Measuring the Electron–Phonon Interaction in Two-Dimensional Superconductors with He-Atom Scattering

2020 ◽  
Vol 5 (4) ◽  
pp. 79
Author(s):  
Giorgio Benedek ◽  
Joseph R. Manson ◽  
Salvador Miret-Artés ◽  
Adrian Ruckhofer ◽  
Wolfgang E. Ernst ◽  
...  
Keyword(s):  
Enhancement Factor ◽  
Coupling Constants ◽  
Phonon Coupling ◽  
Phonon Interaction ◽  
Helium Atom Scattering ◽  
Electron Phonon Interaction ◽  
Atom Scattering ◽  
Electron Phonon Coupling ◽  
Layered Transition Metal ◽  
Mass Enhancement

Helium-atom scattering (HAS) spectroscopy from conducting surfaces has been shown to provide direct information on the electron–phonon interaction, more specifically the mass-enhancement factor λ from the temperature dependence of the Debye–Waller exponent, and the mode-selected electron–phonon coupling constants λQν from the inelastic HAS intensities from individual surface phonons. The recent applications of the method to superconducting ultra-thin films, quasi-1D high-index surfaces, and layered transition-metal and topological pnictogen chalcogenides are briefly reviewed.

AB INITIO STUDY OF PHONON DISPERSION AND ELASTIC PROPERTIES OF L12 INTERMETALLICS Ti3Al AND Y3Al

2013 ◽  
Vol 27 (30) ◽  
pp. 1350224 ◽  
Author(s):  
N. ARIKAN ◽  
M. ERSEN ◽  
H. Y. OCAK ◽  
A. İYIGÖR ◽  
A. CANDAN ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Phonon Dispersion ◽  
High Symmetry ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Phonon Dispersion Curves ◽  
Lattice Constants ◽  
Density Functional Perturbation Theory ◽  
Phonon Properties

In this paper, the structural, elastic and phonon properties of Ti 3 Al and Y 3 Al in L1 2( Cu 3 Al ) phase are studied by performing first-principles calculations within the generalized gradient approximation. The calculated lattice constants, static bulk moduli, first-order pressure derivative of bulk moduli and elastic constants for both compounds are reported. The phonon dispersion curves along several high-symmetry lines at the Brillouin zone, together with the corresponding phonon density of states, are determined using the first-principles linear-response approach of the density functional perturbation theory. Temperature variations of specific heat in the range of 0–500 K are obtained using the quasi-harmonic model.

scholarly journals Origin of the Electron–Phonon Interaction of Topological Semimetal Surfaces Measured with Helium Atom Scattering

2020 ◽  
Vol 11 (5) ◽  
pp. 1927-1933 ◽  
Author(s):  
Giorgio Benedek ◽  
Salvador Miret-Artés ◽  
J. R. Manson ◽  
Adrian Ruckhofer ◽  
Wolfgang E. Ernst ◽  
...  
Keyword(s):  
Helium Atom ◽  
Phonon Interaction ◽  
Helium Atom Scattering ◽  
Electron Phonon Interaction ◽  
Atom Scattering ◽  
Topological Semimetal

Theoretical investigation of elastic and phononic properties of Zn1−xBexO alloys

2015 ◽  
Vol 29 (24) ◽  
pp. 1550140 ◽  
Author(s):  
F. Elhamra ◽  
S. Lakel ◽  
M. Ibrir ◽  
K. Almi ◽  
H. Meradji
Keyword(s):  
Density Functional ◽  
Phonon Dispersion ◽  
Local Density ◽  
Molar Fraction ◽  
Dielectric Constants ◽  
Functional Theory ◽  
Phonon Dispersion Curves ◽  
Density Functional Perturbation Theory ◽  
Pseudo Potential ◽  
Born Effective Charge

Our calculations were conducted within density functional theory (DFT) and density functional perturbation theory (DFPT) using norm-conserving pseudo-potential and the local density approximation. The elastic constants of [Formula: see text] were calculated, [Formula: see text], [Formula: see text] and [Formula: see text] increase with the increase of Be content, whereas the [Formula: see text] shows a non-monotonic variation and [Formula: see text] decreases when Be concentration increases. The values of bulk modulus [Formula: see text], Young’s modulus [Formula: see text] and shear modulus [Formula: see text] increase with the increase of Be content. Poisson’s ratio [Formula: see text] decreases with increased Be concentration. The ductility decreases with increasing Be concentration and the compressibility for [Formula: see text] along [Formula: see text]-axis is smaller than along [Formula: see text]-axis. Phonon dispersion curves show that [Formula: see text] is dynamically stable (no soft modes). Quantities such as refractive index, Born effective charge, dielectric constants and optical phonon frequencies were calculated as a function of the Be molar fraction [Formula: see text]. The agreement between the present results and the known data that are available only for ZnO and BeO is generally satisfactory. Our results for [Formula: see text] [Formula: see text] are predictions.

Phonons in SiC from INS, IXS, and Ab-Initio Calculations

2006 ◽  
Vol 527-529 ◽  
pp. 689-694 ◽  
Author(s):  
Dieter Strauch ◽  
B. Dorner ◽  
A.A. Ivanov ◽  
M. Krisch ◽  
J. Serrano ◽  
...  
Keyword(s):  
Density Functional ◽  
Phonon Dispersion ◽  
Inelastic Neutron ◽  
First Principles Calculations ◽  
Phonon Dispersion Curves ◽  
Functional Methods ◽  
X Ray Scattering ◽  
Density Functional Perturbation Theory ◽  
Phonon Properties

Preliminary results for the phonon dispersion curves of hexagonal 4H-SiC from experimental inelastic neutron (INS) and X-ray scattering (IXS) are reported and contrasted with those of cubic 3C-SiC and silicon. The experimental frequencies and scattering intensities are in excellent agreement with those from first-principles calculations using density-functional methods. The relative merits of the two experimental techniques and aspects of the density functional perturbation theory and the so-called frozen phonon method for the determination of the basic phonon properties are briefly outlined.

Surface-phonon dispersion curves and the longitudinal resonance in Ag(001) observed by helium-atom scattering

1994 ◽  
Vol 50 (12) ◽  
pp. 8897-8900 ◽  
Author(s):  
N. Bunjes ◽  
N. S. Luo ◽  
P. Ruggerone ◽  
J. P. Toennies ◽  
G. Witte
Keyword(s):  
Helium Atom ◽  
Phonon Dispersion ◽  
Dispersion Curves ◽  
Phonon Dispersion Curves ◽  
Helium Atom Scattering ◽  
Surface Phonon ◽  
Atom Scattering

Reststrahlen band studies in cubic perovskite materials SmXO3 (X = Al,Co) by computational investigations

2020 ◽  
Vol 34 (21) ◽  
pp. 2050206
Author(s):  
A. Afaq ◽  
Abu Bakar ◽  
Nimra Khan ◽  
Anila Asif
Keyword(s):  
Optical Phonon ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Infrared Region ◽  
Vibrational Properties ◽  
Imaginary Frequency ◽  
Phonon Dispersion Curves ◽  
Perovskite Materials ◽  
Density Functional Perturbation Theory ◽  
Quantum Espresso

A theoretical study of SmXO3 ([Formula: see text], Co) cubic perovskites for vibrational properties and Reststrahlen band is done within the framework of Density Functional Perturbation Theory (DFPT) implemented in Quantum ESPRESSO. The vibrational properties of the Samarium-based perovskites are figured using Martins–Troullier pseudo potentials. The phonon density of states and phonon dispersion curves in first Brillouin zone are computed and discussed in which two optical phonon frequencies, [Formula: see text] and [Formula: see text], are targeted to find Reststrahlen band for these materials. No imaginary frequency was noted, which shows the structural stability of both perovskites in cubic state. Reststrahlen bandgap and Lyddane–Sachs–Teller (LST) relation for these materials are calculated using optical phonon frequencies and applications are specified. Reststrahlen band of both materials is found to exist in the Far Infra-red region (ranging from 0.3 to 6.0 THz) showing that they can be identified by throwing light of Infrared region upon them in geological applications.

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